Alkyl aryl ethers are excellent solvents for organic residues and are particularly good for dissolving the resinous or varnish-like deposits formed in the crankcase of internal combustion engines. They are also used as antioxidants, heat-transfer agents, and ingredients in perfumes. So far as can be determined, no efficient and economical method is known whereby alkyl aryl ethers can be prepared in desirable quantities. The Williamson synthesis appears to be the most important method involving the reaction between an alkali metal salt of a hydroxy aromatic compound like phenol or cresol and an alkyl halide or sulfate ester. The yields are generally low and there is a disposal problem with the alkali metal salt by-products. Phenols are reported in British Pat. No. 600,837 (Chem. Abst. 42:7334e) to be alkylated with an alcohol using an alumina or silica catalyst to give mixtures of alkylated phenols and phenolic ethers, the latter being produced in about 43 wt. % yield by recycling unreacted phenol. U.S. Pat. No. 2,655,546 discloses the synthesis of alkyl aryl ethers at 65.degree. C. from phenol and olefins using acid catalysts such as sulfuric acid, chlorosulfonic acid, benzenesulfonic acid, alkyl acid sulfates and the like. The disadvantage of this and other such methods involving acid catalysts is that product separation and purification involves aqueous alkali metal hydroxide washes to neutralize and remove the catalyst. The current invention attempts to overcome some of the heretofore mentioned difficulties by providing a synthesis method for the preparation in high selectivity of alkyl aryl ethers from phenols and olefins at ambient conditions employing a heterogeneous catalyst such that a subsequent neutralization step with alkali metal hydroxides is unnecessary.
Accordingly, it is an object of this invention to provide a novel process for the preparation of ethers.
Another object of this invention is to provide a process for the preparation of ethers wherein the product comprises O-alkylated materials.
Other objects, aspects, as well as the several advantages of the invention will be readily apparent to those skilled in the art upon reading the specification and appended claims.